In the related art, liquid compositions used as, for example, daily necessaries, food, and products for the human body such as cosmetic preparations contain two liquids immiscible with each other, for example, water and liquid oil, ethanol and liquid paraffin, or liquid paraffin and a certain ester compound, as media for active ingredients.
Specific examples of certain liquid cosmetic formulations include those constituted by a water-based liquid composition containing a water-soluble component as an active ingredient in a medium of water, and an oil-based liquid composition containing an oil-soluble component as an active ingredient in a medium of a liquid oil immiscible with water. Such liquid cosmetic formulations are formed as an emulsion composition by the action of a surfactant.
However, since such a liquid cosmetic formulation undergoes separation between the aqueous phase (water-based liquid composition) and the oil phase (oil-based liquid composition) during a long-term storage, the liquid cosmetic formulation needs to be emulsified when it is applied. Furthermore, the surfactant may cause skin irritation at application sites or the like. In addition to these problems, a particular problem may arise depending on the intended use, specifically, the type of active ingredient used.
For example, in liquid cosmetic formulations for beauty products, vitamin C and vitamin C derivatives which are active ingredients for skin whitening are water-soluble substances, whereas vitamin E and vitamin E derivatives which are active ingredients for antioxidation are oil-soluble substances. It is thus difficult to maintain the stability (formulation stability) of these two active ingredients in the emulsion composition.
For example, liquid cosmetic formulations for sunscreens need to contain a large amount of oil medium for dissolving an ultraviolet absorbing component because such liquid cosmetic formulations for sunscreens contain an ultraviolet absorbing component as an active ingredient. When water is added to improve feeling during use, a large amount of surfactant needs to be added. A large amount of surfactant tends to cause skin irritation and sticky feeling instead of comfort during use at application sites or the like.
As a cosmetic preparation composed of a liquid cosmetic formulation, there is provided a preparation placed in a container and containing a water-based liquid composition and an oil-based liquid composition with these liquid compositions separated from each other.
Before application to an application site, however, such a cosmetic preparation requires mixing the water-based liquid composition and the oil-based liquid composition well on the palm after taken from the container. This process is burdensome. In addition to this problem, there is another problem in that sticky feeling is caused instead of comfort during use.